Field of the Invention
The invention relates to a method, an apparatus and a computer program for visually supporting a practitioner with the treatment of a target area, in particular a tumor, of a patient by using a treatment agent to be introduced into the target area through at least one supply blood vessel by using a medical instrument, wherein a region of interest which describes the target area and a safety region which surrounds the region of interest at a first distance are defined in an image data record which shows the target area.
New treatment methods, particularly in tumor therapy, propose the local application of treatment agents, for instance medicines, radiopharmaceuticals, chemotherapeutics and the like, directly in the target area to be treated, in particular a tumor. To this end, a medical instrument is guided through the blood vessels of the patient as far as a supply vessel for the target area, where the treatment agent can be introduced into the blood stream and is transported to the target area. A catheter can be used in particular as a medical instrument. In most cases the treatment takes place with visual support, which means that image data records of the target area (and the anatomical region including the same) are recorded, in particular intraoperatively, in which the course of the blood vessels, the target region, and when the intervention is monitored, also ideally the medical instrument, can be identified. In that way by administering a contrast agent, angiography recordings can be recorded as an image data record, for instance, in which the blood vessels in the anatomical region including the target area can be clearly identified. A practitioner must now decide on the basis of the course of the blood vessels which at least one blood vessel is particularly suitable as a supply vessel for the target area and will expose surrounding tissue to the treatment agent as little as possible.
Highlighting aids and the like were already proposed in the prior art in order to further improve the visual support. Support software for radiology already frequently uses detection algorithms in that case, in order to be able to identify objects of interest in clinical image data records. In the presence of large structures, the visualization can be easily adapted by smoothing the shapes of the object. The problem is, however, complicated if there are many small structures, which may be important to the practitioner. One example of such small structures are the aforementioned supply vessels for navigation and treatment planning, for instance in so-called TACE treatment procedures (Transarterial chemoembolization).
Methods for the fully automatic detection of blood vessels in image data records, for instance the x-ray image data records used explicitly in that context, were already proposed in the prior art. Reference is made merely by way of example to U.S. Pat. No. 7,953,266 B2 and U.S. Pat. No. 8,073,227 B2, which address the modeling of vascular trees in digital medical images.
In concrete support of the local treatment of a target area, in particular a tumor, by using a treatment agent through supply vessels, to further support the practitioner it was already proposed to firstly automatically and/or manually define a region of interest (ROI) which describes the target area. In order to be able to determine all relevant blood vessels that may be suitable as supply vessels, provision can then be made to define a safety region at a first distance about the region of interest. Algorithms such as those cited by way of example can now detect blood vessels within the safety region about the region of interest. Those blood vessels are then continued as far as a reference point (“proximal point”) in a supply blood vessel supplying the anatomical region in which the target area is located. A support display which can be generated therefrom shows the corresponding candidates for supply vessels, in particular it overlays image data of the image data record, so that an improved orientation is provided for the practitioner, particularly if the support display also shows the medical instrument during the navigation.
Since a large number of blood vessels are typically present in the safety region surrounding the region of interest, such a support display, in which detected blood vessels are additionally shown or highlighted, can quickly become confusing and unclear for a practitioner. It was thus proposed in that case only to display the blood vessels to be displayed from a specific size, which may, however, also be confusing for the person carrying out the treatment, since further blood vessels can be identified in the image data therefor, which are frequently also shown in the support display, in which it is unclear whether the blood vessel is merely not shown or was incorrectly not detected.